A plasma display panel (PDP) is an element for realizing images by activating phosphor in a vacuum by ultraviolet rays of gas discharge. A plasma display device using such a PDP is in the spotlight as a thin next generation display device because it can enable high resolution and a wide display area.
Such a plasma display device includes a PDP, a base chassis disposed in parallel with the PDP, a heat conducting material disposed between and closely adhered to the PDP and the base chassis, and a driving circuit disposed to the base chassis at its side opposite to the PDP and connected to the PDP for the drive of the PDP. In addition, a front cover is adopted to cover the PDP, and a rear cover covers the driving circuit.
A plasma display device structured as such generates noise and heat when the driving circuit drives the PDP. The rear cover is provided with a plurality of ventilation holes for radiating the heat to outside of the device.
While the ventilation holes radiate the heat, they also enable noises to exit therefrom, for example, a noise generated at a driving circuit such as an X-board, a Y-board, and an SMPS, and a noise generated at the PDP.
As an example of an effort to solve such a problem, Korean Laid Open patent publication 2000-033625 discloses an active noise-annihilation apparatus that generates a noise-annihilation signal having the same amplitude as but with an inverse phase to the noise. However, according to such a scheme, a means for generating the noise-annihilation signal is required, which is complicated and therefore expensive, and accordingly the manufacturing cost of a plasma display panel increases.
In addition, variation of the ventilation holes is limited by regulations.
The ventilation holes are usually of the dimension of 3-5 mm in diameter such that a test pin with a diameter of 4 mm and a length of 10 cm should not contact a dangerous voltage (3 Vpeak) through the ventilation holes. The exemplary dimensions of the test pin are in accordance with the IEC60065 specification for a television, and they may have a diameter of 3 mm and a length of 1.5 cm according to the IEC60950 specification for a monitor.
Therefore, according to such regulations regarding safety, there is not much room for variation in the shape of the ventilation holes, and accordingly, only limited amount of noise reduction could be achieved by varying the shape of the ventilation holes.